Kitchen tap back nut

[Gozza]

Hi all
I have a problem which is annoying me: I need to take out the tap in my kitchen fitting, to trace a leak which I'm fairly sure is in the last little bit of cold water pipe leading up to the mixer tap. The trouble is that the back nut is countersunk into the underside of the worktop, and any tools I've got that are big enough to grip the nut, are too big to go into the countersink. And of course any tool i try to use fouls on the electrical wires and water pipes.
I've tried gripping the base of the tap from above and turning it that way, but the only bit of the tap that doesnt swivel is a ring a couple of mils thick.
Any ideas gratefully received...I'm not averse to buying a new tool if needed, as long as it doesn't cost the earth. My backup position is to slather the whole joint with sugru and see if that cures the leak, but I'd rather make a proper job of it.

Cheers all
A wet and greasy Gozza

 

[Damian]

You need a long box spanner.
If you get a set of these they will do a lot of awkward jobs.

http://www.screwfix.com/p/box-spanner-set-8pcs/4883f

 

[Sproket]

Gozza

What sort / make of tap have you got fitted ?

 

[Gozza]

It's a Reich lever mixer tap. I reckon the back nut is about 33mm across the flats - measured by the scientific method of holding my 27mm gas spanner up to it and guessing how much too small it was.

 

[Sproket]

would this do ?

 

[Gozza]

Thanks Sir Sproket, i will do a proper measure before I order but that might just be the doodad I need.

 

[colin-yorkshire]

It's a Reich lever mixer tap. I reckon the back nut is about 33mm across the flats - measured by the scientific method of holding my 27mm gas spanner up to it and guessing how much too small it was.

hi Paul,
are you sure it is 27mm that is an awfully big nut for a tap [bout the size of the average caravan stub axel nut]
a domestic mixer tap has one that is only 12/13mm. some even 10mm.
ps I have the posh super duper set of tap spanners designed for the job, what are they >>>> " long box spanners 3 of"
well spotted Damian.

 

[Gozza]

are you sure it is 27mm that is an awfully big nut for a tap [about the size of the average caravan stub axel nut]

I'm not certain, I'm going to have another go at measuring it but it's buried up inside the worktop and of course the incoming hot and cold water pipes are in the way of seeing properly too. As I said, I held my gas bottle spanner up to it to see if that was the right size and it was about 5 mil too small. My biggest adjustable spanner won't open wide enough to get on the nut; my Mole grips will, but then the jaws are too wide to get into the countersink.
I will update on progress as it happens - my next step is to cut a card gauge in 32 mm and see if that is the right size next time I'm passing the storage site (prob tomorrow after work), then order a box spanner to suit.

Thanks everyone for the help so far.

 

[Gozza]

It's just occurred to me reading back through the thread that at no point have I made it clear that it's the kitchen tap in the caravan I was talking about! Sorry if anyone thought I meant the one at home!